From the outset, SFC played a crucial role in defining safety guidelines for valve operations in the oil & gas and chemical processing industries. Our modular key-operated interlocks became integral to hazardous process environments, preventing human error and ensuring safe, continuous operations. These innovations quickly gained international recognition, with most offshore installations in the North Sea and onshore processing facilities across Europe implementing our systems.

By the 1990s, SFC had become synonymous with valve interlock safety systems, with major oil & gas operators on all five continents relying on our expertise. We introduced safety solutions for pig launching and receiving operations, ensuring the complete isolation of pig trap vessels, an approach now integrated into international standards such as API and ASME.

The development of the linear key concept by Smith Flow Control revolutionized safety in the oil, gas, and process industries, providing a fail-safe, intuitive, and highly reliable solution for controlling critical valve operations. Unlike traditional rotating keys, linear keys enforce a strict, step-by-step sequence, eliminating human error and preventing hazardous misoperations. Their simple push-pull mechanism makes them easy to use, while their robust, low-maintenance design ensures long-term performance in even the harshest environments.

For 40 years, our commitment to safety has driven us to develop smarter, more reliable valve solutions. As part of the Halma group, a global leader in safety, health, and environmental technologies, we continue to innovate and evolve, delivering cutting-edge products that protect people and critical infrastructure.

From our origins as the inventors of valve interlocking to our position today as the world’s largest valve interlock manufacturer, Sofis remains dedicated to safeguarding people and processes. We are proud of our heritage, and as we look to the future, we remain committed to engineering solutions that enhance safety and efficiency across industries worldwide.

Today, our technology is trusted by major industrial players across various sectors, including energy & process, tank storage, water & wastewater, EPC projects, hydrogen, carbon capture, transport and storage, biofuels, wind, chemical, and marine & FPSO industries. By working closely with local and international partners, we ensure that customers, wherever they are, receive the best possible service, technical expertise, and tailored solutions.

Henry Langston, CEO at Sofis:

“For 40 years our innovative linear key technology has made process industries safer, protecting people, plant and planet. Since then, we have continued to innovate, helping our customers with the solutions to operate safer and more efficiently, making sure their employees go home safely and that their assets operate as best in class. Since 1985 when we were founded, the fatal accident rate in oil and gas production has reduced from 14 per 100 million hours worked to 1, an incredible improvement we’re proud to have contributed towards. Today we continue this legacy by working on the next generation of innovations that will help reduce this rate even further.”

We remain committed to enhancing industrial safety, efficiency, and reliability worldwide to protect people, property, and the planet.

Find out how team members and partners of Sofis have grown with Sofis, what drives them, and what the journey has meant to them!

• Celebrating 40 years of safer valve operations: How Teksal and Sofis turned partnership into legacy
• The evolution of valve interlocks: A conversation with Ian Binney, Key Account Manager EPC projects